Known as "window wire" this is a fine example of almost waste free manufacturing. The triangles cut from the sheet metal strip were used for bale ties which they also manufactured. The only waste was the holes punched in the pointed end of the bale ties for attaching a wire. Would be interesting to know if they managed to use the holes for something, kinda like donut holes.
This wire was used barbless or with barbs by cutting one of the legs and bending the barbs opposite.